Line of Sight (LOS) Analysis
provides the means to determine what portions of the battlefield
are visible from a given position on the battlefield.
Viewregion LOS
allows us to determine what portions of the
battlefield are visible from a region of points on the battlefield.
Here, we will consider the LOS of the position
occupied by Battery B, Fourth US artillery, where it made
its stand against Hood's Texans near the Miller Cornfield.

The position occupied by Battery B at this critical moment of
the battle is found from the
Atlas of the Battlefield of Antietam, plate 4, 7:20 am,
detail shown in Figure X.1.
The battery's position is marked 'Campbell', for the commander of the battery.

Figure X.1

Figure X.2 shows the viewregion LOS of this region, where the viewregion
is defined as the position occupied by the battery,
shown as the brown shaded rectangular region.

HighestVisibilityFromViewRegion

LowestVisibilityFromViewRegion

(a)

(b)

Figure X.2

Figure X.2 (a) is a color coded LOS viewregion LOS map that illustrates
what portions of the battlefield are visible from Battery B's position.
X.2 (b) is a color key used to interpret the colors found in X.2 (a).
Areas in black are invisible from Battery B's position.

From Figure X.2, the southward LOS--the direction the battery
is facing--is limited.
For the purposes of this study, trees and corn are considered to
provide concealment, and therefore block LOS.
As a result, the Miller cornfield and the West Woods tend to block
LOS to both the east and west.
Furthermore, the ground rises steeply to the south, blocking LOS
in that direction.

This analysis would conclude the position is a precarious one,
particularly for artillery, which depends on longer range visibility
to avoid being overrun; the record bears this out, as the fight
is described as a desperate one.
It is perhaps unusual for artillery to become so closely engaged with
infantry.
In this case, the shape of the ground is largely responsible: both
sides are concealed from each other until they approach
very closely, where they finally emerge in front of each other.